When a user captures a video, sounds, or when the user takes a photograph, this capture takes the form of a digital file which is saved in the memory of the apparatus which has allowed for the capture. Without the user being generally aware, the file is encoded beforehand in such a way that it is recorded in a compressed format, in order to limit its size and the quantity of memory required to save it. The size of such a compressed file is of upmost importance when the latter has to be saved in a memory of low capacity, for example that of a portable apparatus; this is in particular the case for digital cameras, portable telephones, or “general public” video cameras.
The compression format is generally chosen according to its compatibility with applications that in particular allow it to be read or post-processed, directly on the apparatus or on an apparatus to which the file has been transferred. However, the compatible and widely distributed formats are generally frozen, or change little, in order to maintain this compatibility; They as such do not benefit from the latest advances in terms of the compression rate and quality although at the same time the number and the size of the files captured is constantly increasing, at the same time as the quality requirements of the users.